Kinetics based evidence for intermediate phase in Ge15Te85 - In-x(x) chalcogenide glasses

This paper presents the thermal studies carried out using Differential Scanning Calorimetry on Ge15Te85 - In-x(x) glasses (1 <= x <= 11) to fmd glass transition temperature, T-g and crystallization temperature, T-x. Further, the variation of T-g and T-x for different heating rates have been studied. The composition dependence of T, T-g and stability factor, Delta T have been investigated. The crystallization kinetics has been studied by a non-isothermal method; the activation energy of crystallization, E-x has been determined using Kissinger method whereas glass transition activation energy, E-g using Kissinger as well as Tool-Narayanaswami-Moynihan (TNM) methods for all the compositions. The results obtained reveal the opening of an intermediate phase, IP in the composition range 2 <= x <= 7. T-g, T-x and Delta T increases continuously across the IP region. The E-x exhibits a plateau and E-g follow a bell shaped curve in the IP region